This invention relates to the recovery of at least copper and nickel from a concentrate containing copper and nickel minerals.
The specification of U.S. Pat. No. 5,919,674 describes a process for the recovery of copper which includes the following steps:
(a) biologically oxidising copper sulphide concentrate in slurry form to dissolve copper as soluble copper sulphate; PA1 (b) subjecting the slurry to solid/liquid separation to produce a solution with a high copper concentration; PA1 (c) treating the solution with a solvent extraction reagent so that copper ions are exchanged by the reagent for hydrogen ions to produce a raffinate which is high in sulphuric acid and low in copper sulphate; PA1 (d) stripping the solvent extraction reagent with a sulphuric acid solution; PA1 (e) electrowinning copper from the sulphuric acid solution; and PA1 (f) using at least a portion of the raffinate from step (c) in step (a). PA1 (a) biologically oxidising the mineral concentrate in slurry form to dissolve copper as soluble copper sulphate and nickel as nickel sulphate; PA1 (b) subjecting the slurry to solid/liquid separation to produce a solution with a high copper and nickel concentration; PA1 (c) treating the solution with a solvent extraction reagent so that copper ions are exchanged by the reagent for hydrogen ions to produce a raffinate which is high in sulphuric acid and low in copper sulphate; PA1 (d) stripping the solvent extraction reagent with a sulphuric acid solution; PA1 (e) electrowinning copper from the sulphuric acid solution; PA1 (f) using a portion of the raffinate from step (c) in step (a); and PA1 (g) recovering nickel from the raffinate which remains after step (f).